The present invention relates to dampers, and in particular, to a damper for machining operations.
Machining processes include a wide variety of manufacturing processes that are used to form a workpiece from raw material. An example of a machining process includes a milling process. Milling processes move a cutting tool across a workpiece to remove material from the workpiece.
Workpieces that are thin and have a high aspect ratio can be subject to chattering during machining processes due to their inherent flexibility. Chattering is rapid vibrations caused by machining processes. In milling processes, specifically, the interrupted cutting action of the cutting tool causes the chattering in the workpiece. Chattering produces waviness on the machined surface, a poor surface finish, and profile errors in the workpiece. Chattering can also result in delamination of composite workpieces.
Dampers can be used to dampen chattering during machining processes. Numerous damping solutions that exist face challenges. A first damping solution is to create a flexible damping sheet to support the workpiece, however flexible damping sheets are typically only effective over a narrow range of frequencies. This limits the speed at which the cutting tool can be turned and restricts the flutes on the cutting tool to avoid reaching frequencies outside of the range covered by the flexible damping sheet. A second damping solution is to use an elastomeric damper that can be attached to a workpiece, however the effectiveness of elastomeric dampers decreases as they age and can vary with temperature changes. A third damping solution is to fabricate complex fixtures to support and hold workpieces, however custom, complex fixtures can be expensive to produce. Further, once a complex fixture has been made, it can be time consuming and costly to adapt the fixture to accommodate design changes in the workpiece. A need exists for a simple workpiece damper that can dampen a broad spectrum of frequencies, is easy to install on and remove from a workpiece, has a low cost to manufacture, and can be easily adapted to accommodate design changes in the workpiece.